Higher Density Air Bubble marks on film - Cause?

[DanK]

Would someone please remind me what the usual cause for higher density air bubble marks on film is?

Slightly darker obvious air bubbles on film (light in print...)

Adox Pan 25 - Rodinal 1:100 - heavily dilute stop - Ilford Rapid Fix (liquid) 1:4

4x5 - 2 L dark tank development

Thanks in advance,
Dan

[Bob Salomon]

Usually caused by not dislodging the air bells during processing. With a Combi tank this was done by gently tapping the Combi against the table once it was full of developer. With hangers by tapping the hanger against the side of the tank. Also could be a sign of improper agitation. That was why the Combi tank had an air space so when it was inverted the chemistry would flow to displace standing chemistry.

[DanK]

Thanks Bob,

I'm using tanks and hangers, and faithfully 'tap'...

Thinking more towards the wash phase, with the bubbles being higher density....

Was under the impression bubbles in the developer phase are typically lighter areas on the neg?

Thanks,
Dan

[Bob Salomon]

Thanks Bob,

I'm using tanks and hangers, and faithfully 'tap'...

Thinking more towards the wash phase, with the bubbles being higher density....

Was under the impression bubbles in the developer phase are typically lighter areas on the neg?

Thanks,
Dan

Is the wash water clean? No sediments? Hard or soft? Running water with sufficient force?

[DanK]

Hard water - city water - w/inline sediment filter - Running - flow rate is enough for complete change of water every 5-6 minutes...but, no large (1/8") or larger bubbles have ever been obvious... (largest bubble mark on film 1/8" - 3 bubbles total one sheet, 2 other)...

Stumped...always same setup, first occurrence...

Thanks,
Dan

[DanK]

to finish out the process...

Developer - no pre-soak - first 1 min, 10 sec every 1 min - stop constant agitation - fix agitate first 1 min, 10 sec @ 30 sec thereafter...

I run a 45min wash, then...final rinse - distilled water soak 5min with few drops photo flo, hang dry from corner (not in hanger)...

Currently thinking maybe air bubbles on film, post fix early wash? or maybe post stop early fix?

Thanks,
Dan

[Doremus Scudder]

...
Currently thinking maybe air bubbles on film, post fix early wash? or maybe post stop early fix? Thanks, Dan

I would tend to think that as long as you fix adequately after the bubble has dislodged, there would not be an issue with added density. However, if a bubble prevented proper fixing, i.e., left some undeveloped halides in the emulsion, then re-fixing would solve the problem. Have you tried re-fixing? Same thing is washing was not adequate - rewash; although I can't think how bubbles in the wash would affect density.

Every time I've got areas of higher density on my negatives, it's been due to contaminated fingers/gloves... Could your bubbles be fingerprints? Are they exactly round (as a good bubble should) or are they a different shape?

A scan would sure help.

Best,

Doremus

[DanK]

Thanks Again Doremus and Bob,

Actually turned out to not be processing related....perfect circle, hard edges - looked like dark bubbles...

Was lens flare....(tiny RR lens, stopped all the way down (from a folder) @ 1:1)...

I originally shot the two negs, different exposures - lost 2 of the flares in the texture on one neg...

Set the shot up again, and noticed the pattern on a new negative...

Appreciate the comments.

Cheers,
Dan